The cat (Felis catus), also known as the domestic cat or housecat[5] to distinguish it from other felids and felines, is a small, usually furry, domesticated, carnivorous mammal that is valued by humans for its companionship and for its ability to hunt vermin and household pests. Cats have been associated with humans for at least 9,500 years,[6] and are currently the most popular pet in the world.[7] Owing to their close association with humans, cats are now found almost everywhere in the world.
Cats are similar in anatomy to the other felids, with strong, flexible bodies, quick reflexes, sharp retractable claws, and teeth adapted to killing small prey. As crepuscular predators, cats use their acute hearing and ability to see in near darkness to locate prey. Not only can cats hear sounds too faint for human ears, they can also hear sounds higher in frequency than humans can perceive. This is because the usual prey of cats (particularly rodents such as mice) make high frequency noises, so the hearing of the cat has evolved to pinpoint these faint high-pitched sounds. Cats also have a much better sense of smell than humans.
Despite being solitary hunters, cats are a social species and use a variety of vocalizations, pheromones and types of body language for communication. These include meowing, purring, trilling, hissing, growling, and grunting.[8]
Cats have a rapid breeding rate. Under controlled breeding, they can be bred and shown as registered pedigree pets, a hobby known as cat fancy. Failure to control the breeding of pet cats by spaying and neutering and the abandonment of former household pets has resulted in large numbers of feral cats worldwide, with a population of up to 60 million of these animals in the United States alone.[9]
As The New York Times wrote in 2007, "Until recently the cat was commonly believed to have been domesticated in ancient Egypt, where it was a cult animal",[10] but a study that year revealed that the lines of descent of all house cats probably run through as few as five self-domesticating African Wildcats (Felis silvestris lybica) c. 8000 BC, in the Near East.[4] The earliest direct evidence of cat domestication is a kitten that was buried alongside a human 9,500 years ago in Cyprus.[11]

Is it true that it's recommended to change exhaust no earlier than 5000 km on your car?

Thanks in advanced!

It's true that brand new exhausts need some time to work in. The pours in the exhaust fill in with carbon deposits changing the tone of the exhaust. Usually making the sound deeper. 5K should be more then enough time to notice a change in the sound.